The 801's strength is in driving demanding cans like HD800s; with low impedance cans it distorts heavily:

I'd suggest getting and O2/ODAC combo for the desktop and a separate DAP. Unless you want to drive really low efficiency phones, a Sansa Clip is excellent once it is Rockboxed. This combo will cost a lot less, should sound better, and you won't give a damn if the DAP gets eaten by a tiger.

Basically I have $800 and want a desktop dac/amp combo and a portable dap. Then I find that HM-801 can do-it-all. So which one do I chose?

Note that I listen to music at home more so dac/amp are more important to me.

First I would say, take your time and read some reviews and info on devices you are interested in. You have a reasonable budget for a DAC/AMP so now it is just a question of finding one that suits your needs.

Try the dedicated source component thread also as thatis really what you want.